Omnipolarization microstrip antenna



N 1955 M. G. CHATELAIN 3,233,330

OMNIPOLARIZATION MICROSTRIP ANTENNA Filed May 28, 1962 liw 4+ Fig.2

E m W I 1] Fig. 3

INVENTOR. MAURICE G. CHATELAIN United States Patent 3,283,330OMNIPOLARIZATION MICROSTRIP ANTENNA Maurice G. Chatelain, San Diego,Calif., assignor to The Ryan Aeronautical Co., San Diego, Calif.

Filed May 28, 1962, Ser. No. 198,323 Claims. (Cl. 343-785) The presentinvention relates generally to antennas and more particularly to anomnipolarization microstrip antenna.

The primary object of this invention is to provide a microstrip antennasensitive to radiation with linear polarization or circular polarizationin either direction, with substantially constant gain.

Another object of this invention is to provide a microstrip antennacomprising a rigid unitary structure with no adjustable or moving partsto become loose or detached.

A further object of this invention is to provide an antenna which iscompact, light in weight and adaptable to a variety of uses andinstallations.

Finally, it is an object to provide a microstrip antenna of theaforementioned character which is simple and economical to manufactureand which contains a minimum of component parts.

With these and other objects definitely in View, this invention consistsin the novel construction, combination and arrangement of elements andportions, as will be hereinafter fully described in the specification,particularly pointed out in the claims, and illustrated in the drawingwhich forms a material part of this disclosure, and in which:

FIGURE 1 is a perspective view of the complete antenna;

FIGURE 2 is a top plan view thereof;

FIGURE 3 is an enlarged sectional view taken on line 33 of FIGURE 2 androtated 90 degrees; and

FIGURE 4 is a similar sectional view showing an alternative mounting forthe microstrip.

Referring now to FIGURES 1-3 of the drawing, the antenna comprises anelongated, conductive microstrip mounted on a plate-like conductiveground plane 12, said microstrip being supported in spaced parallelrelation to the ground plane by posts 14 and 16 of insulative material.The post 14 may be hollow, as in FIGURE 3, for passage of a connection18 to microstrip 10, the other antenna connection 20 being made to theground plane 12. Along each side of microstrip 10 in spaced parallelrelation thereto is a linear array of monopole radiating elements 22,extending from ground plane 12 and inclined outwardly from saidmicrostrip. The angle of inclination of monopoles 22 relative to themicrostrip 10 is preferably 45 degrees for best omnipolarizationcharacteristics, but could be some other angle for specific purposes.For instance, it may be desirable to increase sensitivity to aparticular polarization while maintaining general omnipolarizationqualities. The monopoles 22 on one side of the microstrip 10 arelongitudinally staggered in relation to those on the other side and allmonopoles are nominally one quarter wavelength in length.

Bandwidth of the antenna can be varied by a logarithmic periodicvariation in the size and spacing of the monopole radiating elements.The radiation pattern of the antenna is endfire and directivity isproportional to the antenna length and number of radiating elements.

The linear arrays of monopoles 22 together with their images on theother side of ground plane 12, eitectively constitute dipole arrays onopposite sides of the microstrip transmission line 10. Incidentradiation, in any direction of polarization, excites the monopoles 22,which in turn excite the microstrip 10. Some monopoles will be 5 excitedmore than others, depending on the polarization of the incidentradiation, but the total amplitude of the signal received in themicrostrip will be substantially constant.

An alternative support for the microstrip 10 is illusl0 placed by adielectric block 24 of suitable thickness to hold the microstrip in itscorrect spaced relation from ground plane 12. The dielectric block 24preferably extends the full length of microstrip 10 and may also extendlaterally to provide additional support for the monopoles 22. Thedielectric material is, of course, selected to maintain the correctphase relationship in the antenna.

The simplicity and compactness of the antenna make it adaptable tovarious uses, the light weight making it feasible to attach or build theantenna into aircraft, missiles, or space vehicles. In fact the skin ofany such vehicle, if conductive, may be utilized as a ground plane,since it is not essential for the ground plane to be entirely fiat. Thesize of the antenna will be dependent on the frequencies to be handledand the specific use of the antenna.

It is understood that minor variation from the form of the inventiondisclosed herein may be made without departure from the spirit and scopeof the invention, and that the specification and drawing are to beconsidered as merely illustrative rather than limiting.

I claim:

. 1. An omnipolarization microstrip antenna, comprismg:

an elongated, conductive microstrip;

a conductive ground plane;

said microstrip being fixedly supported in spaced relation from andsubstantially parallel to said ground plane;

a linear array of longitudinally spaced radiating elements extendingfrom said ground plane on each side of and substantially parallel tosaid microstrip;

said linear arrays of radiating elements being inclined in oppositedirections relative to said microstrip.

2. An omnipolarization microstrip antenna, comprisan elongatedconductive microstrip;

a conductive ground plane;

said microstrip being fixedly supported in spaced relation from andsubstantially parallel to said ground plane; a linear array oflongitudinally spaced radiating elements extending from said groundplane on each side of and substantially parallel to said microstrip;

said radiating elements being outwardly inclined on opposite sides ofsaid microstrip.

3. An antenna according to claim 2 and including a dielectric blockfixed to said ground plane and said microstrip and supporting themicrostrip.

4. An antenna according to claim 2 wherein said radiating elements areinclined at 45 degrees relative to said microstrip.

5. An omnipolarization microstrip antenna, compris- 65 ing:

an elongated, conductive microstrip;

a conductive ground plane; said microstrip being fixedly supported inspaced relatrated in FIGURE 4, in which the insulated posts are retionfrom and substantially parallel to said ground 7 g References Cited bythe Examiner a 323 array of longitudinally spaced radiating ele UNITEDSTATES PATENTS ments extending from said ground plane on each side2,629,004 11/1953 Lindenblad 343 705 of and substantially parallel tosaid microstrip; 5 7/1960 343-895 X said radiating elements beingoutwardly inclined on op- 3016536 1/1962 Fublm "*1 X Posite sides ofsaidmicrostrip; 3,096,520 7/1963 Ehrenspeck 343 s24 X and the radiatingelements on one side of said microstrip being longitudinally staggeredwith respect to HERMAN KARL SAALBACH P'mmry Exammer' the radiatingelements on the other side thereof. 10 E.- LIEBERMAN, AssistantExaminer.

1. AN OMNIPOLARIZATION MICROSTRIP ANTENNA, COMPRISING: AN ELONGATED,CONDUCTIVE MICROSTRIP; A CONDUCTIVE GROUND PLANE; SAID MICROSTRIP BEINGFIXEDLY SUPPORTED IN SPACED RELATION FROM AND SUBSTANTIALLY PARALLEL TOSAID GROUND PLANE; A LINEAR ARRAY OF LONGITUDINALLY SPACED RADIATINGELEMENTS EXTENDING FROM SAID GROUND PLANE ON EACH SIDE OF ANDSUBSTANTIALLY PARALLEL TO SAID MICROSTRIP; SAID LINEAR ARRAYS OFRADIATING ELEMENTS BEING INCLINED IN OPPOSITE DIRECTIONS RELATIVE TOSAID MICROSTRIP.